British light heavyweight Joshua Buatsi earned a win yet disappointing beginning to his career under new promoters with a decision win over Parker in Manchester.
The Olympic bronze medallist's work rate appeared to earn him a majority decision in a competitive ten-round bout at the boxing arena.
But Parker found success, landing some telling clean blows in a contest where the styles never quite clicked, with frequent clinching marring the contest.
The officials scored it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my best performance but how do champions respond? They win," Buatsi said in the ringside as he was met by negative reactions from the spectators.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in February - to earn a 20th pro success.
Some ringside observers thought Parker, 31, deserved the win but the Derbyshire fighter suffered the second loss of his 28-fight career.
The Champion Earns Victory in Uneventful Match
The fighter's advancement has plateaued in the past few years through management issues and considerable time of inactivity.
Once tipped as the future of UK boxing, he now finds himself trying to realize his potential - perhaps in what feels like a final roll of the dice - under fresh management.
He started carefully, with neither fighter prepared to be aggressive in a cagey opening few rounds.
Parker, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was participating in his second appearance at the higher weight class.
By the halfway stage, Parker had kept it close, creating difficulties for Buatsi, who worked behind a tight guard to barely take the cleaner rounds.
The crowd's patience wore thin during constant clinching, with the challenger going down multiple occasions during close exchanges.
Parker finished the stronger, but several stanzas were challenging to assess. However, former world champion the boxing analyst - providing analysis for the broadcast network - had it particularly wide for the challenger, awarding Buatsi just a single round.
The victor progresses, but with the caliber of heavy hitter Benavidez, and Russian star Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the co-main event, Arthur overcame Bradley Rea by close verdict in a excellent all-Manchester battle to secure the European light-heavyweight championship.
The venue fell silent for a profoundly moving tribute ahead of the contest as 10 bells rang in memory of local hero Hatton, who died at age 46 in last month.
It was the initial significant broadcast fight night in the city since the passing of Hatton. As the concluding sound faded, the stillness gave way to a roar of "there's just one Ricky Hatton".
The fighting within the ring matched the sentiment. Arthur was sent to the canvas by a significant blow directly to the chin in the early round, rising shakily to his feet on the eight count.
But the traditional red equipment of Arthur soon advanced again. From the other corner, the opponent - in competitive blue - was damaged soon, heavy swelling developing under his orbital area as the fighters landed hard punches.
Rea, twenty-seven, landed power punches but the champion, thirty-four, fought fire with fire with stinging uppercuts as the action seldom decreased over twelve rounds.
The victor barely secured the result with scoring tallies of draw, 115-113 and wider gap, but both fighters were relentless and brave, everything their idol Hatton stood for.
